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BUG: KCSAN: data-race in detach_buf_split / virtqueue_add

read to 0xffff888101acd848 of 4 bytes by task 15943 on cpu 0:
 virtqueue_add_split drivers/virtio/virtio_ring.c:553 [inline]
 virtqueue_add+0x4b3/0x20e0 drivers/virtio/virtio_ring.c:2133
 virtqueue_add_inbuf+0x53/0x80 drivers/virtio/virtio_ring.c:2212
 request_entropy drivers/char/hw_random/virtio-rng.c:61 [inline]
 copy_data drivers/char/hw_random/virtio-rng.c:74 [inline]
 virtio_read+0x1c5/0x3f0 drivers/char/hw_random/virtio-rng.c:92
 rng_get_data drivers/char/hw_random/core.c:197 [inline]
 rng_dev_read+0x1a7/0x5e0 drivers/char/hw_random/core.c:234
 vfs_read+0x19e/0x580 fs/read_write.c:468
 ksys_read+0xeb/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read-write to 0xffff888101acd848 of 4 bytes by interrupt on cpu 1:
 detach_buf_split+0x2fc/0x570 drivers/virtio/virtio_ring.c:757
 virtqueue_get_buf_ctx_split drivers/virtio/virtio_ring.c:835 [inline]
 virtqueue_get_buf_ctx+0x3c2/0x5b0 drivers/virtio/virtio_ring.c:2327
 virtqueue_get_buf+0x1f/0x30 drivers/virtio/virtio_ring.c:2333
 random_recv_done+0x4c/0x90 drivers/char/hw_random/virtio-rng.c:42
 vring_interrupt+0x150/0x170 drivers/virtio/virtio_ring.c:2501
 __handle_irq_event_percpu+0x91/0x490 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:210
 handle_edge_irq+0x167/0x590 kernel/irq/chip.c:819
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq arch/x86/kernel/irq.c:231 [inline]
 __common_interrupt+0x3c/0xb0 arch/x86/kernel/irq.c:250
 common_interrupt+0x7a/0x90 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636
 bpf_send_signal_common+0x19b/0x230 kernel/trace/bpf_trace.c:874
 ____bpf_send_signal kernel/trace/bpf_trace.c:879 [inline]
 bpf_send_signal+0x19/0x20 kernel/trace/bpf_trace.c:877
 ___bpf_prog_run+0x281/0x3050 kernel/bpf/core.c:1828
 __bpf_prog_run32+0x74/0xa0 kernel/bpf/core.c:2049
 bpf_dispatcher_nop_func include/linux/bpf.h:1168 [inline]
 __bpf_prog_run include/linux/filter.h:600 [inline]
 bpf_prog_run include/linux/filter.h:607 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2269 [inline]
 bpf_trace_run2+0x92/0x130 kernel/trace/bpf_trace.c:2308
 __bpf_trace_sys_enter+0x9/0x10 include/trace/events/syscalls.h:18
 __traceiter_sys_enter+0x4a/0x70 include/trace/events/syscalls.h:18
 trace_sys_enter include/trace/events/syscalls.h:18 [inline]
 syscall_trace_enter kernel/entry/common.c:81 [inline]
 __syscall_enter_from_user_work kernel/entry/common.c:94 [inline]
 syscall_enter_from_user_mode+0x12d/0x190 kernel/entry/common.c:112
 do_syscall_64+0x22/0xc0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15958 Comm: syz-executor.1 Tainted: G        W          6.4.0-rc7-syzkaller-00072-gdad9774deaf1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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virtio_rng virtio3: input:id 1 is not a head!